Stacked-tape trapped-field superconducting magnets - Edging ahead?

Abstract

Conventional permanent magnet materials, such as NdFeB, have remanent magnetisations which are intrinsically limited to less than 1.5T. Somewhat higher fields can be achieved using Halbach arrays [1] but progress in developing higher performance materials is challenging [2]. Conversely, in a superconducting pseudo-permanent magnet the trapped magnetic field arises due to macroscopic transport currents flowing in what is essentially a single turn coil. Consequently, the maximum achievable trapped magnetic field scales with the radius of the magnet. Such pseudo-permanent superconducting trapped field magnets can exhibit trapped fields of over 17 T which have the potential to find wide applications [3].